You should have 0 ammonia, 0 nitrites and 10-20 nitrates. Your tank is not cycled.

But it has been cycled since Summer when I set it up.When I tested it last night there is Zero Ammonia and Zero Nitrites and I don't remember the Nitrate number cause I'm here at the library's computers since the Snow storm Blizzard we got a few days ago took out my internet connection days ago But there are some Nitrates in there.

The Petsore owner tested it yesterday and it tested perfectly. He said all the numbers are where they should be. So I'm not sure what to say....

Yes, the tank filter has carbon and the ammonia absorbing white granuals mixed it with it. (AmmoCarb?) I have been changing it every other day now. I put it in a seperate filter media bag with the regular filter cartridge behind the Bio filter pad.

I am just treating the whole tank cause there is nothing to cup them in. I am useing the Bifuron right now. The Bettas look a little better but still not wanting to eat much of anything. Only one more Betta has died since adding the Bifuron. But One Oto has died and the Cory Catfish look like they have fuzzy fins and mouths now and act sick plus wont eat.

Well, it looks like a few of us feel like you really should take them out of the tank somehow to make sure the tank itself isn't causing the problem.. you can get extremely cheaply some 1 or 2 gallon acrylic bowls and keep them warm by floating in the larger tank.. but if you want to go this route it's up to you.

I would stop feeding Hikari. NLS and Atison's are ok if you want to alternate.

pictures don't look like parasites or anything else. Look more like water quality issue. If they clamp.. kinda hang around not moving you often have ammonia. I skimmed over the posts so don't know if you posted water parameters.. if you have anything BUT zero ammonia and nitrite you have toxic water. Prime can help with ammonia.. but major water changes will be needed to get under control. And a cycled tank does not stay cycled when adding and subtracting fish. If you added meds to kill bacteria infection you killed what will convert your ammonia to the nitrite and finally nitrate. Basically wiped out your biological filtration.. So with the med probably came huge ammonia spike. Get some water changes done. lots of them in the next few days and if you don't have a test kit for ammonia.. the drops.. get one so you know your water.

I recommend jarring them somehow anyways. IF there is a chance something is floating around you would have a better chance keeping them individually. Go out and buy a few jars, dollar tubs, anything. Even kitchen stuff would work for now (rinsed very very well). Trust me it is in your best interest to make sure your fish survive.

Adding the bottom feeders all at once could cause the tank to have higher ammonia, therefore now going through a new cycle. HOWEVER if you have 0.25 ammonia, the bettas have come in cups with up to 5.00 ammonia and survive miraculously. I don't know if the bottom feeders are even more hardy than that, but I still recommend jarring the bettas.

Then you have to re-cycle your tank. Since the meds and new additions have come in, the cycle basically no longer exists. Which is why I use meds sparingly and always ALWAYS quarantine... healthy looking or not! Never add more than 2-3 fish (depending on tank size, for your tank it's fine) at a time otherwise you risk an ammonia spike.

If you can get the bettas jarred somehow, you can float them in the tank to keep the temperature up. Use tape or something to hold them still so they do not float away. Clean the water every day, adding water of the same temperature.

Has anything in the tank changed other than new arrivals? New conditioner? New food? New heater? New gravel?